The invention relates to a gas diffusion electrode (GDE), also known gas diffusion layer (GDL), namely for a membrane electrode assembly (MEA), comprising a membrane and a gas diffusion electrode contacting the membrane, of a fuel cell, in particular a hydrogen oxygen fuel cell, or of an electrolysis device, in particular an electrolysis device for electrolysis of water. Moreover, the invention concerns a method for producing a gas diffusion electrode.
Gas diffusion electrodes are generally known in the prior art. They are used in performing electrochemical processes, for example, in fuel cells or in electrolysis devices that are embodied as membrane electrolyzer.
US 2003/0162081 A1 discloses a gas diffusion electrode that is comprised of an electrically conducting catalyst support and an electric connector, wherein the catalyst support serves for receiving the catalyst material. As a catalyst support, a fabric, nonwoven, foam or felt of electrically conducting material, an expanded metal plate or a metal plate provided with a plurality of openings is employed onto which the catalyst material is applied. In this context, for forming a dimensionally stable gas diffusion electrode, the catalyst support is fixedly connected mechanically and electrically conductingly with a gas-permeable metallic base plate, in particular made of nickel or its alloys, by sintering. An advantage of this configuration is that, despite the open structure of the catalyst support for receiving the catalyst material, a comparatively shape-stable gas diffusion electrode is provided which is achieved by the comparatively stiff substructure of the base plate which takes on the function of an abutment when pressing the catalyst material into it.
US 2008/0245662 A1 discloses an electrolytic cell and, for providing an electrode with great specific surface area, proposes to configure the cathodes and/or anodes as multi-layer expanded metal electrodes which are comprised of at least two expanded metal layers and of an edge electrode that are contacting each other by means of internal resistance zones. The expanded metal layers each are positioned on a base plate and are arranged in a cell trough or in several electrode frames clamped to each other. For further enlargement of the specific electrode surface area, porous intermediate layers are preferably arranged between the expanded metal layers.
U.S. Pat. No. 6,071,386 discloses also an electrolysis apparatus which comprises a plurality of membrane electrolysis cells each provided with a membrane that is provided on both sides with a contact layer. On each of the contact layers a contact plate is arranged so that the electrolysis apparatus, while having a compact configuration, is also suitable for comparatively high hydrogen production rates and is thus usable in a particularly flexible way. Each contact plate is provided with a channel system for transport of water and/or gas on its surface that is facing the associated contact layer.
U.S. Pat. No. 5,804,055 discloses an electrode for an electrochemical cell. In this context, the electrode is a porous multi-layer electrode which is provided with a flexible strip-shaped element that is wound about a central core which is in general of a flat configuration. Each layer of the electrode can be formed of a very thin, highly flexible metal mesh.
U.S. Pat. No. 3,907,513 discloses a composite material with predetermined porosity. The composite material comprises a plurality of screens which are bonded to each other in parallel arrangement. In this context, into the meshes of each screen, spherical particles are inserted that have a diameter substantially reducing the size of the mesh openings.
US 2006/0014451 A1 discloses a method for producing a porous plate-shaped metal composite. The metal composite is produced from metal fibers which are compressed and welded or fused to each other in one working step.
U.S. Pat. No. 8,067,097 B2 discloses a woven laminate as a liner for sound absorption of inlet and outlet sound absorbers. The laminate comprises at least three stacked woven layers that are at least partially fused to each other. One layer has a coarse structure compared to the others, another a fine structure, and the remaining woven layer has a structure between coarse and fine. The woven layers are composed of metallic wires that are interwoven or are intertwined to a nonwoven metallic wires
Even though fuel cells and electrolysis devices as well as the gas diffusion electrodes that are used therein are known in numerous configurations, there is still a need for improvement. It is therefore the object of the invention to propose a novel gas diffusion electrode that, due to its constructive configuration, can be used flexibly and provides great versatility.